Navigation Links
Immune police recognize good and bad guys in the body
Date:9/14/2007

Immune system police are as good at recognizing bad guys, such as bacteria and viruses, as they are our own tissue, researchers say.

The finding may cause a stir in the scientific community, which has long held that regulatory T cells or Tregs, preferentially respond to body proteins, or self antigens, rather than non-self antigens, invaders such as viruses and bacteria.

Now, Medical College of Georgia immunologists report in the September issue of Immunity that Tregs, similarly to other T cells, respond stronger and more frequently to foreign substances than to the bodys own antigens.

Fortunately, the potential conflict between nave and regulatory T cells, in which the former lead the attack against invaders and the latter try to protect invaders, usually doesnt exist, the scientists say.

That?s probably because other types of immune cells come to help T cells fight an infection, says Dr. Rafal Pacholczyk, a corresponding author for the study.

During the normal immune response, Tregs sit in the back seat and, in most cases, dont interfere, says Dr. Leszek Ignatowicz, also a corresponding author.

Still, emerging therapies to fight autoimmune diseases, such as arthritis, multiple sclerosis and type 1 diabetes, by boosting the total number of Tregs could unintentionally upset the balance between nave T cells and Tregs, they say.

Regulatory cells always suppress immunity, whether it?s to a virus, bacteria or our own tissue, says Dr. Ignatowicz.

We have to be really careful with manipulating regulatory T cells as a whole, adds Dr. Pacholczyk. If we want to promote more regulatory cells in the body, we have to find a way to promote only those in which specificities are known.

Oral insulin, which appears to boost the number of Tregs that recognize and protect insulin-producing pancreatic cells from the immune system, is a good example of how this targeted promotion may work for type 1 diabetes, they say.

To determine what antigens Tregs can recognize, Drs. Pacholczyk and Ignatowicz did side-by-side studies of antigen receptors expressed on nave T cells and Tregs.

Here, we could quantitatively compare proportions of how many regulatory cells or how many non-regulatory cells see non-self versus self antigens, and we found these proportions to be similar,? says Dr. Ignatowicz. We found regulatory cells respond to cells presenting non-self antigens as frequently as nave T cells.

Researchers report that 70 percent of the most frequent receptors found on na ve T cells also were found on Tregs. Since receptors define what the individual T cell recognizes, it provides additional evidence that nave T cells and Tregs see the same thing, they say.

Drs. Pacholczyk and Ignatowicz reported in the August 2006 issue of Immunity that Tregs, like na ve T cells, learn what to recognize in the thymus. They also reported that most Tregs that mature in the thymus retain their regulatory properties and do not later convert to nave T cells as was previously believed. This finding emphasized the role of the thymus as the primary site where Tregs differentiate and acquire their unique inhibitory functions, they say.

Although, the majority of T cells that may harm healthy body tissue are eliminated in the thymus, some errant autoreactive cells can escape and cause autoimmune disease. Tregs previously believed to primarily recognize self-tissue with the idea of protecting it are considered the antithesis of these autoreactive cells.

It was believed that regulatory cells are baptized autoreactive cells, says Dr. Ignatowicz. They are like bad boys that went good, since they also recognize self tissue but seek to protect it.

Yet scientists kept running into the reality that some regulatory cells also were recognizing and potentially protecting invaders such as bacteria and viruses.

The MCG scientists say because both T cell populations are educated in the thymus, it is not surprising that they recognize the same things.


'/>"/>

Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
Source:Eurekalert

Related biology news :

1. Fox Chase Cancer Center scientists identify immune-system mutation
2. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
3. Genetically modified natural killer immune cells attack, kill leukemia cells
4. Studies reveal methods viruses use to sidestep immune system
5. Jumping gene helps explain immune systems abilities
6. Scientists solve structure of key protein in innate immune response
7. Rats infected as newborns grew up vulnerable to memory problems during an immune challenge
8. NYU study reveals how brains immune system fights viral encephalitis
9. Chemists identify immune system mechanism for methamphetamine binges
10. Multi-purpose protein regulates new protein synthesis and immune cell development
11. Genetically Modified Natural Killer Immune Cells Attack, Kill Leukemia Cells
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/3/2016)... Calif. , March 3, 2016  FlexTech, a ... the categories of Innovation, Research & Development, Leadership in ... Leadership. This is the 9 th year of ... group of companies and individuals from past years ... based on a pre-described set of criteria, by a ...
(Date:3/3/2016)... SOTO, Kansas , March 3, 2016 ... Oncimmune,s Early CDT®-Lung, a blood test to aid ... cancer Early CDT®-Lung test to its clients ... Early CDT®-Lung test to its clients which include ... a leader in early cancer detection, today announced a ...
(Date:3/2/2016)... , March 2, 2016 ... of the "Global Biometrics as a ... offering. --> http://www.researchandmarkets.com/research/cmt3hk/global_biometrics ) ... "Global Biometrics as a Service Market 2016-2020" ... --> Research and Markets ( http://www.researchandmarkets.com/research/cmt3hk/global_biometrics ...
Breaking Biology News(10 mins):
(Date:5/3/2016)... WOODLANDS, Texas , May 3, 2016  Dr. ... certified plastic surgeon in The Woodlands, Texas ... that destroys 24 percent of treated fat cells in ... and woman. Close to 90 percent of Americans report ... treatment options. Nonsurgical fat reduction procedures are a growing ...
(Date:5/2/2016)... ... ... StarNet Communications Corp, ( http://www.starnet.com/ ) a leading publisher of remote Linux ... to its flagship X-Win32 PC X server. The new modules enable X-Win32 to ... over encrypted SSH. , Traditionally, users of PC X servers deploy the XDMCP protocol ...
(Date:4/29/2016)... 2016 According to a ... "Separation Systems for Commercial Biotechnology Market - Global ... 2015 - 2023", the separation systems for commercial ... in 2014 and is projected to expand at ... to reach US$ 19,227.8 Mn in 2023. ...
(Date:4/28/2016)... PUNE, India , April 28, 2016 ... PT, JT, Stirling, and Brayton Cryocoolers), Service (Technical Support, ... Application, and Geography - Global Forecast to 2022", published ... to USD 2.94 Billion by 2022, at a CAGR ... Browse 70 market data Tables and 94 Figures spread ...
Breaking Biology Technology: